In the electric power converter, for example, as shown in FIG. 1 of Japanese Patent Laid-open No. Hei 3 (1991)-218270, to remove high-frequency components generated in an AC line and a DC line, a capacitor is connected between the AC line and the DC line. The converter compares signal waves of respective phases having a phase difference from one carrier common to the respective phases, gives positive logic and negative logic high frequency pulses, which are output of comparators, to switching devices to control the PWM.
When a function for removing the high-frequency components generated in the AC line and DC line is provided, the following advantages can be obtained.
(1) Without insulating the AC line and electric power converter by a transformer, a leakage current Ir can be reduced.
(2) A high-frequency current leaking from the electric power converter is reduced, so that an EMI countermeasure can be taken.